1. Technical Field
The present invention relates to a joint connector, and more specifically to a double-sided joint connector for joining two other mated connectors jointed with both the joint openings formed on both the sides of the joint connector.
2. Description of the Related Art
FIG. 1 shows an example of a related art double-sided joint connector, which is disclosed in Japanese Published Unexamined Utility Model Application No. 56-115878. In FIG. 1, this joint connector 1 is composed of a connector housing 2 having a first (front side) joint opening 2A and a second (rear side) joint opening 2B both joined with two other mated connectors (not shown), respectively, and a plurality of bus bars 3 and 4 housed in the connector housing 2.
In the related art joint connector 1, one bus bar 3 is formed with a single base terminal portion 5 extending frontward from the inside of the connector housing 2 and two branched terminal portions 6 extending rearward from the inside of the connector housing 2. On the other hand, the other bus bar 4 is formed with a single base terminal portion 5 extending frontward from the inside of the connector housing 2 and three branched terminal portions 6 extending rearward from the inside of the connector housing 2. These two bus bars 3 and 4 are housed within the connector housing 2 being arranged side by side horizontally (in the right and left direction) in such a way that the ends of the branch terminal portions 6 are arranged in a line within the rear joint opening 2B of the connector housing 2.
The shapes of these bus bars 3 and 4 are different from each other, and further the arrangement of the terminal portions 5 and 6 of these bus bars 3 and 4 are different from each other when viewed at the front and rear joint openings 2A and 2B. In more detail, when seen from the front joint opening 2A side (in the direction of arrow A in FIG. 1), the base terminal portions 5 are arranged as shown on the lower side in FIG. 2A, and when seen from the rear joint opening side 2B (in the direction of arrow B in FIG. 1), the branch terminal portions 6 are arranged as shown also on the lower side in FIG. 2B. That is, the terminal end portions 5 or 6 are arranged in a different way on both the front and rear joint openings 2A and 2B, respectively. Further, in FIGS. 2A and B, the bus bars 3 and 4 are shown by solid lines, and the respective terminal portions 5 and 6 which can be seen from either side are shown by black squares to facilitate the mutual positional relationship between the base terminal portions 5 and the branch terminal portions 6.
In the related art double-sided joint connector as described above, when a mated connector 7 is inserted into the front joint opening 2A and another mated connector 8 is inserted into the rear joint opening 2B respectively, as shown in FIG. 3, these two mated connectors 7 and 8 can be connected to each other through the double-sided joint connector 1.
Here, FIG. 4A shows a correct connection. Under these conditions, the mated connector 7 is joined to the front joint opening 2A of the joint connector 1 in such a way that a terminal end portion 7a of one mated connector 7 is in contact with the base terminal portion 5 of the bus bar 3, and the other mated connector 8 is joined to the rear joint opening 2B of the joint connector 1 in such a way that the branched end portions 6 of the bus bars 3 and 4 are in contact with the terminal end portions 8a to 8e of the other mated connector 8. Through the above-mentioned connection, since the terminal end portions 8a to 8c of the mated connector 8 are connected to each other, and in addition since the terminal end portions 8d and 8e are connected to the terminal end portion 7a of the mated connector 7, respectively, it is possible to form a required electric circuit.
In the above-mentioned double-sided joint connector, however, there exists such a possibility that the two mated connectors 7 and 8 are joined to the double-sided joint connector erroneously in the opposite way. When the two mated connectors 7 and 8 are connected to the joint connector 1 correctly, a correct electric circuit as shown in FIG. 4A can be established. However, when connected in the opposite way, it is no longer impossible to form a correct electric circuit, as shown in FIG. 4B. In more detail, when the two mated connectors 7 and 8 are joined to opposite sides of the joint connector 1 erroneously, the terminal end portions 8a to 8c of the mated connector 8 are not connected to each other, and further the terminal end portions 8d and 8e of the mated connector 8 are not connected to the terminal end portion 7a of the mated connector 7.